$OpenBSD: patch-arp-scan_c,v 1.1 2015/04/14 14:17:20 sthen Exp $
--- arp-scan.c.orig	Tue Apr 14 14:29:22 2015
+++ arp-scan.c	Tue Apr 14 14:57:22 2015
@@ -133,6 +133,10 @@ main(int argc, char *argv[]) {
  *      Process options.
  */
    process_options(argc, argv);
+   if (getuid() != 0) {
+      fprintf(stderr, "ERROR: arp-scan must be started with root privileges.\n");
+      exit(1);
+   }
 /*
  *      Get program start time for statistics displayed on completion.
  */
